This early example of dealer-installed wireless joins the several burgeoning plans that want to bring the information super highway to the highway. But some wonder if the Web has extended its reach too far. As überconnected drivers cheer, and auto dealers hope for a new hit product during this recession, safety advocates warn that cars don’t need any more distractions.

Cadillac’s new box taps into the Internet through mobile phone signals. It connects to nearby cellular towers and converts the information into a language that most computers understand: Wi-Fi.

“It’s just like going to a Wi-Fi hotspot,” says Christine Williams, public relations manager for start-up Autonet in San Francisco, which designed the Cadillac system.

The box is not a built-in feature. Instead, the carmaker is offering Wi-Fi directly through the aftermarket. Each in-car router fits into the trunk of the CTS and is hard-wired to power up when the driver turns on the engine.

Cadillac sells the boxes for $499 and charges a monthly fee of $29 to $59, depending on usage.

Carmakers traditionally launch new technology in their highest-end brands with the expectation that once adopted by high-income consumers, it will expand to other models. (The CTS sedan costs up to $59,730.)This time, however, the Wi-Fi service might remain within Cadillacs, due to recessionary caution.

“If we have a good experience with this on the first go-round, the next step [would be to] authorize it pretty quickly into other Cadillac vehicles. But I would be little cautious how far into marketplace this can go,” says Mr. Caldwell from Cadillac. “It’s expensive, honestly.... It’s difficult to say at this point in the game where it’s going to go.”

Cadillac’s Wi-Fi rollout is not the first, but it is one of the most direct. Ford and Chrysler have each found success promoting factory-installed multimedia systems that combine some element of Internet access.For instance, Chrysler’s UConnect (also by Autonet) and Ford’s Sync systems are voice-activated. They allow users to send and receive text messages, dial phone numbers without taking their hands off the wheel, and control portable music players. The Chrysler system also includes a router for Wi-Fi access.

Cadillac is not bundling its router inside a branded entertainment service on purpose, says Caldwell.

“We want it to be a little bit customizable,” he says. For systems like Sync or UConnect, “sometimes it may be difficult for consumers to know what’s in there.” Cadillac’s pitch is simple: It works just like a Wi-Fi router in your home or office.

But that instant access while driving is exactly what worries safety advocates. Many argue that there are already too many in-car distractions.

“You have to do something about this now before it becomes a problem as big as drunk-driving,” says Clarence Ditlow, executive director of the Center for Auto Safety, a public policy center in Washington. “When you look at Wi-Fi, you’re looking at something that’s more of a cognitive distraction that takes more of your mind off the road – more than a simple phone call.”

Because it is so new, there is little data that links in-car wireless to auto safety. However, the National Highway Traffic Safety Administration (NTSA) found that cellphone use and other in-car distractions collectively contribute to 25 percent of all police-reported traffic crashes.

Text messaging while driving, one of the most similar in-car activities, is responsible for a 400 percent increase in the amount of time drivers are distracted from the road, according to the NTSA.

“We could call [in-car wireless] an attractive nuisance,” says Janette Fennell, founder and president of Kids and Cars Inc., an automotive advocacy group in Leawood, Kan.

Her group works to temper new technology by warning carmakers about safety hazards they may never have considered.

“We keep blurring the line between a vehicle as a means of transportation and a vehicle as another kind of home,” she says. “Adding these things continues to blur that line.”

Cadillac and Autonet both insist their Wi-Fi hotspot is meant for “passengers only,” says Caldwell. When customers purchase the system, they are warned about the pitfalls of browsing cyberspace while navigating the road.

However, advocates like Mr. Ditlow say simply marketing in-car technology as one thing will not necessarily make it so. A comparison, he says, can be made to the way beer is promoted.

“The alcohol industry says ‘drink responsibly.’ The automotive industry says ‘drive responsibly.’ We don’t want to take devices out of cars. What we want to say is, ‘If you want to use it, park it,’ ” he says. His group is drafting a proposal that makes it standard that whenever a car shifts into gear, its interactive technology shuts down.

But to the tech-savvy consumer, the debate over in-car wireless may be moot. As Chuck Squatriglia of Wired magazine observes, “Who’s going to get an expensive [wireless] system in your car when you have an iPhone in your pocket?”

They both access the Internet through cellphone towers. But the iPhone can leave your car – and, admittedly, costs more per month.

Mr. Squatriglia, who edits the magazine’s Autopia blog, says that regardless of necessity, wireless technology is expected to become the next platform for automotive innovation. Once carmakers master signals transmitting in and out of cars, it opens up intelligent transportation systems that allow cars to “talk” to one another to ease road congestion, and to beam advertisements for local restaurants directly into GPS units. Additionally, carmakers will soon be able to beam software updates or recall notices directly into their vehicles instead of requiring consumers to bring them into dealerships for servicing.

“Wireless is definitely something coming to the auto industry,” Squatriglia says. “You’re going to see more of it than less of it from now on.”